1. Field of the Invention
The present invention relates to a method for testing a motor vehicle on a test track and a test vehicle for conducting the tests on test track.
2. The Prior Art
During the development stage of motor vehicles, it is necessary to create certain driving states in order to test how a vehicle behaves under certain conditions. This can be done on special test stands, for example roller dynamometers, or on test tracks (whether in the form of a real roadway or a special test terrain is not important in this context). Both options have advantages and disadvantages. Test stands do not necessarily allow for any type of duplication that may be desired because they are unable to simulate real ambient conditions with every degree of accuracy. Therefore, testing on a test stand can always only give indications as to the real behavior of the motor vehicle on the real roadway (even if the real conditions are approximated very closely). A test track, in contrast, is naturally limited in terms of its possibilities dependent on its course through different environments, routes, etc. Consequently, it is not possible to generate an unlimited number of desired driving states on a test track. Moreover, a test on a test track depends in most cases also on environmental conditions (temperature, moisture) and the test driver (clutching times, pedal position(s), steering angle, etc.) and is thus not completely reproducible. Nevertheless, by choosing varied test tracks (for example, a route through an urban area or a high Alpine road, the “Grossglockner mountain road”) it is, of course, possible to carry out different test runs on different types of roadways which, as any observer will understand, is a complex undertaking and only possible with limitations.
Known in the art are, for example, braking trailers that are hooked up to the primary vehicle and that are able to exercise braking forces on the primary vehicle, for example by hydraulic or pneumatic brakes on the braking trailer. A braking trailer of this kind is disclosed, for example, in DE 27 55 184 A1. Another braking trailer, as known from DE 10 2004 029661 A1, integrates a controlled load unit that allows for simulating total resistance to vehicular motion as well as trailer loads. The braking effect is achieved by the controlled conversion of mechanical into electrical energy via an electric generator. Consequently, braking trailers of this kind are only able to simulate certain driving states. But they are not suited for implementing comprehensive motor vehicle testing measures under varying driving conditions.
Therefore, it is the object of the present invention to provide a method for testing a motor vehicle as well as a test vehicle that allow for simulating any kind of desired driving states (within the physical possibilities) of a vehicle on a test track.